Gastroesophageal reflux occurs when stomach acid enters the esophagus. This reflux of acid into the esophagus can occur naturally in healthy individuals, but also may become a pathological condition in others. Effects from gastroesophageal reflux range from mild to severe. Mild effects include heartburn, a burning sensation experienced behind the breastbone. More severe effects include a variety of complications, such as esophageal erosion, esophageal ulcers, esophageal stricture, abnormal epithelium (e.g., Barrett's esophagus), and/or pulmonary aspiration. These various clinical conditions that result from reflux of stomach acid into the esophagus are referred to generally as Gastroesophageal Reflux Disease (GERD).
Many mechanisms contribute to prevent gastroesophageal reflux in healthy individuals. One such mechanism is the functioning of the lower esophageal sphincter (LES). FIG. 1A schematically illustrates the esophagus as it would appear in a healthy individual in the region of the LES. The LES 1 is a ring of smooth muscle and increased annular thickness existing in approximately the last four centimeters of the esophagus 3. In its resting state, the LES 1 creates a region of high pressure (approximately 15-30 mm Hg above intragastric pressure) at the opening of the esophagus 3 into the stomach 5. This pressure aids in closing the esophagus 3 so that contents of the stomach cannot pass back into the esophagus 3. The LES 1 opens in response to swallowing and peristaltic motion in the esophagus 3, allowing food to pass into the stomach 5. After opening, however, a properly functioning LES 1 should return to the resting, or closed state. Transient relaxations of the LES 1 do occur in healthy individuals, typically resulting in occasional bouts of heartburn. Also, lack of support for the esophagus at the LES or widening of space of the diaphragm that supports the esophagus often allows a portion of the gastric fundus to protrude up through the esophagus, resulting in movement of the LES and changing the pressures seen at the LES region. This condition, generally referred to as hiatal hernias, is common in the elderly and is one of the major contributing factors in GERD.
Referring to FIG. 1A, the stomach lining 2 is comprised of columnar cells, while the esophageal lining 4 is comprised of squamous cells. These cells are histologically distinct from one another and serve vital functions. For example, while columnar cells are acid resistant, squamous cells are prone to damage by stomach acid. The point at which the cell types transition is known as the “Z-line” 6 and is generally located in a healthy individual at a point below the LES region 1. However, when a healthy esophagus is subject to repeated, prolonged exposure to stomach acid reflux, the cell structure of the esophageal lining 4 changes from the normal squamous cells into the columnar cells and, as shown in FIG. 1B, “fingers” 7 of columnar cells appear in the area of the LES 1. The “fingers” 7 of columnar cells, also known as Barrett's Epithelium, can occur in a patient suffering from chronic GERD.
Since an individual with Barrett's epithelial tissue is many times more likely to develop esophageal cancer than a healthy individual, a surgical resection of the tissue or tissue ablation is often performed. This type of surgical resection of diseased tissue, however, introduces widely dispersed, open wounds that are very painful to the patient and take a long time to heal. These wounds may be prone to infection if the acid is not properly managed through appropriate medications. Other types of wounds or lesions may also be introduced during the natural progression of the disease, which are subject to the same harsh condition present in this part of anatomy.
Therefore, it is accordingly an object of the present invention to provide devices and related methods for treating lesions in the alimentary tract, such as, for example, endoscopic mucosal resection (EMR) sites or esophagus. In particular, the devices and methods promote healing of the lesions by stimulating tissues for rapid healing and/or regrowth while reducing the risk of infection and discomfort of the patient in the least invasive way possible.
In order to eliminate or reduce the need for highly invasive and physiologically insulting surgical procedures, endoscopic techniques have been developed for the diagnosis and/or treatment of certain disorders. Endoscopy allows examination and the manipulation of tools and tissues in interior areas of a patient's body utilizing naturally occurring orifices in the body, such as the alimentary tract. Endoscopic surgery eliminates or greatly reduces the need for the large, surgically-produced openings traditionally required to obtain access to sites deep within the body and, thus, reduces the attendant trauma to skin, muscle, and other tissues. Endoscopic surgery also eliminates or greatly reduces various risks associated with effects of anesthesia during a course of surgery. Consequently, a patient may experience less pain, recover more quickly, and present less scarring.
Therefore, it is accordingly another object of the present invention to provide devices and related methods for endoluminal delivery of the treatment device to a lesion of the alimentary tract, which eliminate or reduce the need for highly invasive, physiologically insulting surgical procedures.